Professor Vardis Ntoukakis

Lipid Remodelling as a Novel Strategy for Antimicrobial Compound Tolerance in Plant Pathogens

Secondary Supervisor(s): Dr Mojgan Rabiey, Professor Yin Chen

University of Registration: University of Warwick

BBSRC Research Themes:

• Sustainable Agriculture and Food (Plant and Crop Science)

Project Outline

Plants produce an extraordinary array of over 100,000 low-molecular-weight natural products, often termed secondary metabolites. Many of these act as antimicrobial agents, forming potent chemical defences against microbial attack. This vast metabolic diversity reflects an evolutionary arms race between plants and pathogens, driving ever more sophisticated defence strategies.

Although many plant antimicrobials show broad-spectrum activity, their impact depends on the pathogen’s ability to resist them. For instance, Botrytis cinerea detoxifies the grapevine phytoalexins via enzymatic activity, Fusarium species deploy efflux pumps to expel toxins, while Pseudomonas syringae uses type III effectors to suppress immunity and block antimicrobial production.

We have recently uncovered an exciting and unexplored defence-evasion mechanism used by major crop pathogens: membrane lipid remodelling. Our data indicate that, during early epiphytic growth on leaves, environmental cues trigger bacteria to remodel their membranes. This process increases tolerance to host-derived antimicrobial compounds, enabling successful colonisation and entry into plant tissues.

Research objective:

To uncover how lipid remodelling contributes to antimicrobial tolerance and virulence across diverse plant–pathogen systems, providing new insights with potential applications in crop protection.

We will focus on three globally important pathosystems:

• Pseudomonas syringae in tomato
• Ralstonia solanacearum in tomato
• Xanthomonas campestris in Brassica oleracea

All three employ lipid remodelling but differ in infection strategy and colonisation sites, providing an ideal comparative framework. This project offers training in cutting-edge molecular, genomic and imaging approaches, preparing you for careers at the interface of plant biology, microbiology, and biotechnology.

CASE: Bridging the Gap Between In Vitro and Whole-Plant Herbicide Screening Using Biosensors

University of Registration: University of Warwick

Non-academic partner: Dr Emma Linney (Syngenta UK Life Sciences), Dr Mark Johnston (Syngenta UK Life Sciences)

Secondary Supervisor(s): Dr Joe McKenna

Project Outline

What?

This project seeks to develop a high-throughput screening platform which spans from protoplasts and cell cultures to seedlings and mature plants, with the goal of enhancing the predictive accuracy of herbicide discovery. The work builds on our recently developed Golden Gate based1 toolbox of luminescence and fluorescence-tagged Arabidopsis biosensors2,3, capable of measuring cellular and physiological responses of protoplasts to environmental perturbations by tracking changes in hormone levels (ABA, auxin, cytokinin, jasmonic acid and salicylic acid), heat stress tolerance, circadian rhythm and organelle morphology and integrity (for the ER, nucleus, mitochondria and Cytoskeleton).

Why?

A major bottleneck in herbicide development is the weak correlation between in vitro activity and realworld performance in plants. This project addresses that challenge by deploying advanced biosensors across a continuum of biological systems and scales, from protoplasts and cell lines to seedlings and whole plants. By systematically linking herbicidal activity to reliable, physiologically relevant readouts, we aim to bridge the gap between early-stage discovery and whole plant phenotypes.

How?

The project will be structured around three core objectives:

1.Toolbox expansion: Optimise and integrate available genetically encoded fluorescent biosensors targeting signalling (calcium, ROS) and metabolic pathways (NAD/H, NADP/H, ATP, inorganic phosphate, glucose, sucrose, along with intracellular pH biosensor. These biosensors will allow tracking of stress signalling and biochemical changes in response to herbicide treatment in real time.

2.Platform Establishment: Generate stable Arabidopsis cell lines and transgenic plants expressing both luminescent and fluorescent biosensors using GoldenGate vectors, allowing the rapid assembly of multi-biosensors constructs. This will enable direct, cross-platform comparisons between protoplasts, cell lines, seedlings and whole plants under herbicide exposure.

3. Herbicide Profiling: Use our robotic liquid-handling platform and imaging pipelines to screen known and novel herbicides, linking changes in hormones, metabolites and organelle morphology and integrity to photosynthetic activity, visible phenotypes and known herbicide modes-of-action across Arabidopsis protoplasts, cell lines, seedlings and adult plants. Herbicides with favourable profiles will undergo further testing in Brassica napus and Brassica oleracea protoplasts using our biosensor toolbox, marking the first step in assessing their activity in crop plants.